Choosing a PDF Accessibility Checker

​Choosing a PDF Accessibility Checker

Many organizations rely on an accessibility checker to confirm whether their PDF documents are accessible. Unfortunately, choosing the wrong tool is one of the most common reasons documents fail WCAG or PDF/UA compliance—even when they appear to “pass” automated checks.

This article explains why some accessibility checkers are unreliable, what standards actually matter for PDFs, and how professional accessibility testing is typically performed.

Can I use the Adobe Acrobat accessibility checker?

The built-in Adobe Acrobat accessibility checker is widely used because it is convenient and readily available. However, relying on it alone is a frequent and costly mistake.

The primary issue is that Acrobat’s accessibility checker does not test against a defined accessibility standard, such as WCAG 2.0 or PDF/UA. The tool performs a general “Full Check” without clearly stating which requirements are being validated or which standards are being met.

As a result, documents may pass Acrobat’s checks while still failing formal compliance reviews.

A common example is list structure. Acrobat does not reliably prompt users to verify list numbering and hierarchy, even though correct list tagging is essential for assistive technologies. Similar gaps exist for reading order, tag semantics, and structural relationships.

Passing the Acrobat checker does not mean a PDF is compliant.

Which PDF accessibility checker should I use?

For technical validation, we recommend the PDF Accessibility Checker (PAC).

PAC evaluates PDF files against the Matterhorn Protocol, which defines the file-format requirements of PDF/UA-1. This protocol maps WCAG 2.0 success criteria directly to PDF-specific requirements.

PAC performs:

• 31 technical checkpoints

• 136 defined failure conditions

• Clear pass/fail reporting against PDF/UA

This makes PAC a far more reliable indicator of technical compliance than general-purpose accessibility tools.

Why automated checking is not enough

Even the best accessibility checker can only evaluate technical structure, not meaning or usability.

Manual inspection is always required to verify issues such as:

• Logical reading order
• Appropriate heading structure
• Meaningful alternative text
• Color contrast interpretation
• Correct use of tags for context and intent

Software cannot interpret content in the same way a human or assistive technology user does. This is why accessibility compliance is never fully automated.

How accessibility testing is typically done

In professional remediation workflows, accessibility testing usually involves:

1. An automated technical validation (such as PAC),
2. Manual inspection by trained specialists
3. Verification using assistive technologies

This combination ensures that documents meet both technical standards and real-world usability requirements.

Conclusion

Accessibility checkers are useful tools—but only when used correctly. Relying solely on Adobe Acrobat’s checker can create a false sense of compliance and lead to failed audits, rejected submissions, or accessibility complaints.

Documents intended to meet WCAG, PDF/UA, AODA, ADA, or Section 508 requirements must be tested against defined standards and manually verified.

When we remediate documents, we ensure they pass both PAC testing and Acrobat checks. Completed PAC reports are provided with all remediated files.

Accessibility Testing Note

If you’re unsure whether your existing PDFs meet accessibility requirements, we offer free accessibility testing. We can verify compliance against WCAG, PDF/UA, and other standards and explain exactly what is required.